As for me and my PCB designer -- we've decided to use Protel 99SE until
it becomes impractical for us.

That is where I was last July after giving DXP a try. However, I got a
project out of the blue that I was not sure could be done in 99SE. At
that point, it was too late to try and switch to a new package. I ended
up doing the project in 99SE with much pain. While I do not see a
similar project on my horizon, I have learned my lesson. It is best to
upgrade on your own schedule rather than wait to be forced to move on
someone else's schedule. That is what I intend to move to the next CAD
system even though 99SE is quite useable for most of what I am doing
today and what I see on my horizon.

Who knows,
they might even offer a deal to convert registered users of other EDA
tools to their software? Much as Protel did with Orcad users several
years ago (when there was a revolt going on after Cadence bought
Orcad). That could be big trouble for Altium.

That would be the final nail in Altium's coffin. If I were to make a
prediction, that is how I see things ending for Altium. Some
competition, either someone moving up from below, or someone moving down
from above will start offering credit for a Protel license and Altium
will not be able to deal with the mass desertion.